The field of the present invention relates to the control of engines in driving engagement with a load through a conventional clutch mechanism wherein the speed of the engine may also be varied. In particular, the field of the invention relates to a clutch and throttle control system of an engine driving a high pressure liquid pump wherein it is desired to operate the engine and vary the speed thereof from a distance physically removed from the engine and pump.
Such remote control systems have been constructed in the past using either all electric or all pneumatic controls for accomplishing the desired change in throttle setting or desired clutch disengagement from the load. However, in prior art pneumatic or electric systems of this type, certain disadvantages arise since in an all-pneumatic remote control system, large pressure drops will occur whenever the remote control station is at a great distance from the engine. Not only will large pressure drops occur due to the long pneumatic control lines, but additionally, as the distance increases from the control station to the engine to be controlled, greater and greater time lag will be introduced due to compensability and pressure drop factors in the pneumatic lines.
In an all-electric remote control system, while the disadvantage of pressure drop and time lag of a pneumatic system is avoided, undesirable high cost of electric throttle and clutch actuators and controls therefor is encountered, thereby making an all-electric remote control system undesirable from an economic standpoint.